Various rating and other systems help viewers control what content is available to their children. The Motion Picture Association of America provides a rating system for movie content that typically assigns a letter rating (G, PG, R, and X) to a movie. Parents have used these ratings, which may be displayed on the outside of a video cassette, other media container, or within the media content itself, to limit their children's access to certain content. In addition, new U.S. television sets have V-chip technology that uses the vertical blanking interval in a television signal to receive a special code indicating a show's score according to a numerical rating system for violence, sex, and language. If the piece of content's rating is outside the level configured as acceptable on a particular television, it is blocked. In these and other contexts, existing rating systems are generally fixed and unchangeable both in the number/categories of ratings and in the particular ratings assigned to any particular piece of content. Existing systems are thus inflexible with respect to changes over time, differences with respect to geographic location, and/or differences with respect to particular user preferences, among other things.